An appellate court is a higher court that reviews decisions made by lower courts, such as trial courts. Its primary function is to determine whether legal errors occurred during the trial that could have affected the outcome. Appellate courts do not conduct new trials or hear new evidence; instead, they focus on the legal arguments presented in written briefs and oral arguments. In the United States, appellate courts are part of a multi-tiered judicial system. Cases can be appealed from state or federal trial courts to intermediate appellate courts, and then potentially to the highest court, such as the Supreme Court. The decisions made by appellate courts can set important legal precedents that influence future cases.